20 January 2021: Soon to be released APP 1.083-beta2 : improved comet registration, updated tools, new Star Reducer Tool and more...
16 November 2020 - Wouter van Reeven has officially joined the Astro Pixel Processor Team as a moderator on our forum, welcome Wouter 🙂 !
Back Ground Neutralisation problems
All day I’ve been trying to stack lights, darks, flats, and dark flats taken on an Altair Astro 294c OSC with a quadband filter. Using pretty much default setting in Adaptive Airy, but with the option for background neutralisation turned off. All seems to stack ok (although sometimes it turns out purple🤷♂️) but as soon as I then select tools - remove light pollution (or background neutralisation) the image changes to ‘blocky’ single colour mess. This gets 100 times worse if I actually select boxes and calculate. It seems it maybe connected to the darks as it is not so bad if I stack without. If I select Neutralise in Normalisation the initial stacked image just comes out as a mass of bright red, the same as selecting the option in tools. Don’t think I have bad darks as I’ve used these from my library on countless times. It’s not the flats or dark flats as it does it without. Each single Light looks to be a good image. What am I doing wrong? APP is version 1.082.
You should use a different algorithm in tab 0. Here you can choose to go for Ha signal, OIII signal and others and combine those later for instance. Here's a workflow for the duoband, but the steps for narrowband extraction can be applied to these filters as well, just using the options in the demosaic algorithm that are comptible with your filter; https://www.astropixelprocessor.com/community/postid/7610/
My guess here is that you mainly have h-alpha signal and very little in the other channels. That means that using a normal algorithm will get very noisy probably.
@vincent-mod thank Vincent but I’ve already tried Ha-OIII colour and it does the same thing. These are from the latest stack the first image is straight from stack (purple which to me says the bayer isn’t correct ? But I’ve had this before on initial stack and it rights itself when selecting Background neutralisation). The second image is on selecting LP removal. Last one is after LP removal calculation
Oeh ok. I need to have a look at the data then to be able to help better;
Please upload some of the relevant subs to our server;
Go to https://upload.astropixelprocessor.com and use upload3 as username and upload3 as password.
Create a directory named “russ-telfer-quadbandissue” and upload in there. Thank you
@vincent-mod. Many thanks Vincent, just tried and Ha and OIII extract and it looks stunning 😊. Every day is a school day.
Ah, haha. That is totally fine Russell, I love to learn anyway so good on you. 🙂 If you have further questions for combining the results etc let me know.